math
Bob finds that the cost of driving his truck is 92 cents per mile. Give a symbolic and graphical representation for a function f(x) that computes the cost in dollars of driving x miles. Assume 0<x<60March 25, 2012

math
I had a total of 129 marbles in 3 boxes at first. Then i away 2/3 of the marbles from box1, added 15 marbles to box 2 and added somes to box 3 until the number of marbles in box 3 tripled. As a result, the ratio of the number of marbles in box 1 to the number of marbles in box...March 13, 2012

Science
A student observed two different types of cells under a microscope. She noticed that one cell had many more mitochondria than the other. What can the student predict about the cell with more mitochondria? A. The cell produces more waste. B. The cell makes more proteins. C. The...February 27, 2012

Chemistry
FIRST U should find whether there is reaction when they are mixed,and then what is the concentration of the mixture.next,find the concentration of H+ ion,finally,use this formular to solve your problem pH =-log[concentration of H+ ]February 26, 2012

CHEM, please help!
A 11 mL sample of a solution of AlBr3 was diluted with water to 23 mL. A 15 mL sample of the dilute solution was found to contain 0.045 moles of Br-. What was the concentration of AlBr3 in the original undiluted solution? answer is 2.09 but i cant get it.February 16, 2012

chemistry
. A 13 mL sample of a solution of AlBr3 was diluted with water to 56 mL. A 25 mL sample of the dilute solution was found to contain 2.21 M Br-. What was the concentration of AlBr3 in the original undiluted solution?February 16, 2012

chemistry
How many milliliters of a 155 mL solution of 1.7 M AlCl3 must be used to make 70 mL of a solution that has a concentration of 0.21 M Cl-?February 16, 2012

chemistry
describe how to prepare a .50 m solution of lead nitrate using only 100.00 mls of water. aslo discribe how to prepare a .50m sloution of sodium iodide using only 100.00 mls of water. explain the differences that exist between these two solutions. OK i have answers for both 1....February 15, 2012

6th grade math
can someone please help me with this question?And can someone also teach me step by step how to solve this question???Please???February 13, 2012

6th grade math
your mother gave you $13.32 with which to buy a present.This covered 3/5 of the cost.how much did the present cost? can someone please help me and also show me how to solve this?February 13, 2012

Math
In a playground, there is a model of the old school building that is 6.6 feet long, 3.3 feet wide, and 4.6 feet high. If the real building was 80 feet long and 40 feet wide, how high was it?February 8, 2012

Pre-Algebra
Please let me know if I figured these out correctly. Directions: For the line with the given equation, find the slope of a parallel line and the slope of a perpendicular line. 1)y=6/5x + 144 slope of parallel: 6/5 slope of perpendicular: -5/6 2)4y-4x=16 slope of parallel: 1 ...January 30, 2012

Math
Please let me know if I figured this out correctly. Directions:Write an equation for the line that is perpendicular to the given line and that passes through the given point. 1) y=x-3; (4,6) Answer: y=-x-10 Thank you!January 29, 2012

trig
This is not trig. Anyway, C=2(pi)r. If the circumference is 12.31, then the radius is 12.31/[(pi)r] = 1.96. If the central angle is 1/4 of a revolution, then the central angle measure is 90 degrees. The area of a sector is a piece of the area of the entire circle: A=(pi)r^2 * ...January 25, 2012

Calculus
Over what open interval does the formula F(x)= int from 0 to x of dt/t represent an anti derivative of f(x) =1/x? Find a point where the graph of F crosses the x axis.January 25, 2012

Calculus
Let F(x)=int from 0 to x of (t-3)/(t^2+7) dt for -infinity <x< infinity. a. Find the value of x where F attains its minimum value. b. find the intervals over which F is only increasing or only decreasing. c. Find open intervals over which F is only concave up or only ...January 25, 2012

Calculus
True or false: If f(x) is continuous on the interval [a,b] & if the definite integral of f(x) over this interval has value zero, then the equation f(x)=0 has at least one solution in the interval [a,b]. True or false: If f(x) is continuous everywhere and F(x)= int from 0 to x ...January 25, 2012

Calculus
First, divide each term in the numerator by the denominator. x/x + sin(x)/x (x/x=1) 1+sin(x)/x The Sandwich (or Squeeze theorem) states that the limit as x->0 of sin(x)/x is 1. 1+1=2 You can ask me more questions on Facebook:Kate Calendrillo, Math Tutor.January 25, 2012

chemistry(balance equation)
hi!i am a f4 student in hk.i have know the basic concept of balance equation.but some too complex equation i cant balance.is there any general short cut for balancing any simple or complex chemical equation?January 19, 2012

English
What conclusion can you draw about Samuel Pepys from his account of the Great Fire of London? A. He maintained relations with all social strata. B He became the spokesperson of the aristocracy. C he felt responsible for organizing rescue missionsJanuary 18, 2012

6th grade science
which of the following lists all the levels of organization in a multicellular organism from the lowest level to the highest level? A)tissues and organ systems B)organ systems,tissues,organs,and cells C)tissues,cells,and organs D)cells,tissues,organs,and organ systems My ...January 9, 2012

Math
Can you please help me set up this equation? Copies at the local library cost $.15 easch. A new copier costs $200 and it costs $.02 to make a copy. How many copies would have to be made for the cost of making your own copies equal to the cost of copying at the library? Thank ...December 19, 2011

Physics
A. Calculate the force on an alpha particle in an electric field E=Exm where E=3.6E4 N/C and x is a unit vector in the x direction. What is the direction of the force? B. Calculate the acceleration of the alpha particle in this electric field. What is the direction of the ...December 11, 2011

Accounting
When Resisto Systems, Inc., was formed, the company was authorized to issue 5,000 shares of $100 par value, 8 percent cumulative preferred stock, and 100,000 shares of $2 stated value common stock. Half of the preferred stock was issued at a price of $103 per share, and 70,...December 9, 2011

chemistry
a sample of 0.002 mole of HCL is dissolved in water to make a 2000mL solution. What is the molarity?December 7, 2011

Chemistry
Given the following equation: N2(g) + 3H2(g) = 2NH3(g). Determine to one decimal place the molar mass of each term, and WRITE EACH ONE AS A CONVERSION from moles to grams.December 5, 2011

6th grade math
In general, the air temperature decreases 12F for every 4000 feet increase in altitude. If a hiker climbs 3000 feet, by how much can she expect the temperature to decrease?December 4, 2011